1. Field of the Invention
This invention relates to an ignition system, utilizing adiabatic heating of gas, for liquid propellants.
2. Prior Art
Liquid propellant guns are well known, and are shown, for example, in U.s. Pat. No. 4,023,463, issued to D. P. Tassie, on May 17, 1977 and in U.S. Pat. No. 4,051,762, issued to E. Ashley, on Oct. 4, 1977. Such guns, firing non-hypergolic propellants, require an initial pulse of hot, high pressure gas in the combustion chamber to start the firing process for each shot. For repetitive firing, sequential pulses must be provided. When pyrotechnic primers are utilized, the expended primer must be replaced after each shot as shown in U.S. Pat. No. 4,051,762. Electric spark ignition will work only with electrically conductive propellants, as shown in U.S. Pat. No. 4,023,463. Non-conductive propellants, such as Otto Fuel II, cannot be easily ignited. They must be confined and exposed to conditions of sufficient temperature and pressure for combustion to occur. U.S. Pat. No. 3,576,103, issued to P. B. Kahn, on Apr. 27, 1971, shows ignition of a monopropellant by adiabatic compression. This is accomplished by compressing a preloaded volume of propellant by means of a spring-loaded plunger which must be manually cocked and seared for each shot.
An object of this invention is to provide a series of adiabatic ignition pulses for non-hypergolic propellants for burst firing.
Another object is to provide each such pulse with an extended, controlled duration.
A feature of this invention is the provision of a booster charge of liquid propellant from a main supply to adiabatically compress a quantity of gas and then progressively inject the booster charge into the heated gas.